1. Field of Invention
This invention relates generally to pouches for safely carrying classified documents or other confidential or valuable material from a sending to a remote receiving station, and more particularly to a security pouch adapted to inform its receiver whether at some point in the course of transit, the pouch had been intercepted and invaded.
2. Status of Prior Art
As used herein, the term "pouch" is applicable to any hand-carried bag, briefcase or container adapted to accommodate documents or other classified material, or to accommodate other valuable articles, such as bank notes or jewelry. The term "sending station," as used herein, refers to the site at which the documents are put in a closable pouch and then locked, while the term "receiving station" as used herein, refers to a site remote from the sending site at which the pouch is unlocked to obtain access to these documents.
It is common practice for federal agencies dealing with classified material, such as the FBI and CIA, to use couriers to hand-carry confidential documents from a sending station to a remote receiving station. The reason these documents are hand-carried is to avoid interception by unauthorized personnel, for one cannot rely on conventional means, such as ordinary mail or Federal Express to safely convey these documents. For like reasons, embassies and consulates make use of diplomatic pouches which are hand carried by couriers.
It is known to provide a security pouch with a key-operated locking mechanism so that documents contained in the pouch cannot be removed without unlocking the pouch. At a sending station, the locked pouch is given to a courier to be taken to a remote receiving station. When the courier arrives at the receiving station, a receiver, using a key matching that used by the sender, then unlocks the pouch to remove the documents.
The problem with relying on matching keys to ensure security is that security in this situation depends on the absence of a third key in the hands of an unauthorized individual. But if this individual has in some way succeeded in obtaining a copy of the key and is able to intercept the pouch at some point in its transit from the sending to the receiving station, he can open the pouch, remove and make copies of the documents or otherwise tamper with them, before returning the documents to the pouch and relocking the pouch.
Yet when the relocked pouch arrives at the receiving station, the receiver has no way of knowing that the pouch had been intercepted in the course of transit if it still contains documents. And if the pouch contains no documents or contains substituted documents, the receiver has no way of knowing when and where in the course of transit the original documents were removed.
Inasmuch as a security pouch in accordance with the invention includes a locking mechanism operatively coupled to an electronic module provided with a random number generator which is activated when the lock is closed, of prior art interest is the electronic seal for document bags being marketed by Encrypta Electronics Limited. Also of prior art interest is the 1995 Hayward U.S. Pat. No. 5,447,344 assigned to Encrypta.
The Encrypta electronic seal takes the form of an electronic module which cooperates with a beaded cord similar to a chain of interlinked beads. One end of this cord is attached to the module, the free end going into a door catch in the module to form a loop. The module is provided with a random number generator and an elapsed time indicator, as well as an LCD display for the random number and the elapsed time reading.
When the Encrypta cord is caught in the door catch in the module to complete the seal, this action causes the display in the module to present a random number. This number is unpredictable, for each time the cord is caught, a new number is generated unrelated to the previous number. When the sealed bag is later delivered, the display then presents the same number as well as the time that had elapsed (days; hours; minutes) from the point in time at which the bag was sealed to the point in time at which the bag was received.
But if the random number presented at the receiving station differs from that presented at the sending station, this is evidence that the seal had been broken and then reclosed before the bag arrived at the receiving station.
A seal in the form of a cord loop is not a locking mechanism, for it serves only to deny access to a closure of some sort. Thus if a document bag is provided with a zipper associated with a locking mechanism that holds the zipper closed, and overlying the zipper locking mechanism is a flap which must be folded out to obtain access to the locking mechanism, a cord seal which loops through the flap prevents the flap from being folded out. Hence only by breaking the seal does one gain access to the locking mechanism.
The concern of the Encrypta electronic seal unit is with the integrity of the seal, not with the operation of a locking mechanism. In a security pouch in accordance with the invention, an electronic module provided with a random number generator and an elapsed time measuring unit is operatively coupled to a locking mechanism associated with the closure means of the pouch.
Since in one embodiment of the invention, the pouch has a zipper whose slider is engaged by the jaws of a locking mechanism, of prior art interest is the Rifkin U.S. Pat. No. 5,065,602.